Naim Audio NAIT XS3

The Naim Audio NAIT XS3 is an integrated amplifier that continues the NAIT series first launched in 1983. Succeeding the XS2, it brings several technical improvements and reintroduces an MM phono preamplifier, a feature that had been absent since the NAIT 3 of the 1990s. The unit delivers 70 watts per channel, includes a Class A headphone stage, and offers extensive connectivity. It is designed to drive both speakers and headphones, while preserving the sonic characteristics associated with Naim products.

Uncompromising technical design

Beneath its compact extruded aluminium chassis lies an impressive array of technologies. The 350 VA toroidal transformer, manufactured by Irish specialist Nuvotem Talema, occupies nearly half of the internal space. Oversized for this category, it guarantees a stable, responsive power supply capable of delivering 100 watts per channel into 4 ohms. Its position, set away from the input circuitry, minimizes electromagnetic interference.

Naim’s engineers have redesigned the power amplification stage compared with the XS2. The voltage gain has been doubled in speed, which also doubles the response speed of the output stage. The transistors in the second gain stage have been optimised, eliminating the need for a protective cascode transistor. This simplification reduces the amplifier’s stabilisation requirements and doubles the slew rate, improving overall responsiveness to fast transient signals.

The circuit uses a Class A/B topology with discrete through‑hole components rather than integrated circuits or surface‑mount parts. This choice reduces the negative effects of vibration and thermal variation. The power transistors benefit from ceramic insulation to optimise heat dissipation while minimising parasitic capacitive coupling. The PCB supports incorporate microphonic isolation to prevent mechanical vibrations from affecting the signal.

The microprocessor control section is galvanically isolated from the audio circuits – a physical separation that prevents digital disturbances from contaminating the analogue signal path. The volume potentiometer comes from Alps’ “Blue Velvet” series, renowned for its precise channel balance (typically less than 2 dB deviation) and its metallised conductive‑plastic track rated for 15,000 operating cycles.

A three‑stage phono preamplifier

The integration of a phono preamplifier is the major new feature of the XS3 – a first for the XS range and a return to Naim’s roots, as no NAIT had offered a phono input since the NAIT 3 of the mid‑1990s. Compatible exclusively with moving‑magnet (MM) cartridges, this circuit is based on a three‑stage topology: initial gain stage, passive equalisation, then final gain and active equalisation.

This functional separation achieves an exemplary signal‑to‑noise ratio, RIAA equalisation extending beyond the audio band, and substantial headroom before overload. All RIAA equalisation capacitors are through‑hole film types, selected for their low sensitivity to microphonic effects and excellent transient characteristics. The 47 kΩ input impedance in parallel with a 470 pF capacitive load is ideally suited to 5 mV cartridges.

Since phono stages are 1000 times more sensitive than line inputs, this attention to components and signal routing translates into faithful reproduction of the subtle details engraved in vinyl. The phono circuit is mounted on its own printed circuit board, with point‑to‑point, hand‑soldered connections – a time‑consuming technique that requires real know‑how, but eliminates PCB tracks that could pick up interference.

Pure Class A headphone amplifier

The XS3’s headphone output is no cosmetic afterthought. It uses an asymmetric (single‑ended) Class A amplifier derived from that of the SUPERNAIT 3, the flagship model in the range. In Class A, the output transistors are constantly biased, eliminating the crossover distortion inherent to Class AB topologies. The additional current allocated to this section ensures optimal drive for headphones, including models with low impedance.

This 6.35 mm jack output turns the XS3 into a high‑end personal listening station. The high‑performance preamplification stage, renowned for its transparency, ensures the same sonic signature in private listening as through speakers. Owners of demanding planar or dynamic headphones will find in this output everything needed to fully exploit their transducers.

Connectivity designed for upgradeability

The XS3’s rear panel reflects the versatility Naim was aiming for. Four inputs accept either RCA connectors or DIN (Naim’s historical format, known for its mechanical robustness and left/right channel separation). A fifth DIN input is also available. The RCA phono input completes this analogue arsenal.

The fixed outputs (130 mV, 600 Ω) allow recording or integration into a multiroom system without affecting the main volume. Variable outputs include a preamplifier output (775 mV, below 50 Ω) that lets you bypass the internal power stage in favour of an external amplifier. A dedicated subwoofer output (RCA, 775 mV) simplifies the addition of a subwoofer. A bi‑amping configuration is even possible via the dedicated DIN output.

The XS3 continues Naim’s tradition of upgradeability. DIN sockets on the rear, linked by a jumper in normal use, allow the addition of an external Naim power supply (FlatCap XS, HiCap or SuperCap). This modularity enables a gradual upgrade path without changing amplifier. A mini‑USB port allows control‑firmware updates. The supplied Narcom5 infrared remote controls volume, source selection, and standby.

Improvements over the NAIT XS2

Six years separate the XS2 (2013) from the XS3 (2019). Naim did not seek to reinvent a product that already worked well, but to refine it. The addition of the phono preamplifier is the most visible evolution, responding to the vinyl resurgence. On the electronics side, doubling the speed of the voltage‑gain stage and optimising the second gain stage bring greater responsiveness and nuance in transients.

The ALPS Blue Velvet potentiometers replace the previous models. Ceramic insulation for the power transistors improves thermal stability. PCB supports with microphonic isolation and the galvanically isolated control section strengthen immunity to interference. These changes, although subtle on paper, combine to deliver a measurable gain in clarity, dynamics, and bass control.

Since December 2024, the XS3 has adopted white LEDs instead of the traditional green ones – an aesthetic detail that modernises the front panel without betraying Naim’s visual identity. The translucent semi‑circular logo remains in place, illuminated when the unit is powered on.

Technical specifications

Power and amplification

• Output power: 70 W per channel into 8 Ω at 0.1% total harmonic distortion plus noise
• Output power: 100 W per channel into 4 Ω at 0.1% total harmonic distortion plus noise
• Class A headphone amplification
• Optimized gain stages with doubled slew rate
• Cascode transistor removed for reduced stabilization and improved sound quality

Inputs and outputs

• Analog inputs
  • 4 RCA or 5-pin DIN inputs: CD, Tuner, Stream, AV
  • 1 x 5-pin DIN input: Aux / Phono with 24 V power supply
  • 1 MM phono input: 47 kΩ / 470 pF impedance, gain matched for 5 mV MM cartridges
  • Line sensitivity: 130 mV, 47 kΩ impedance
• Analog outputs
  • 2 fixed-level line 5-pin DIN outputs: 130 mV / 600 Ω
  • 1 variable RCA Sub output: 775 mV / less than 50 Ω
  • 1 variable 5-pin DIN Pre-out output: 775 mV / less than 50 Ω
  • 1 x 6.35 mm jack headphone output

Audio features

• Transparent preamplification for pure sound
• 3-stage phono section: ultra-low noise, extended RIAA equalization, wide overload margin
• Through-hole film RIAA capacitors for low microphony and precise transients
• Reed relay input selection
• Ceramic insulators for power transistors
• Galvanic isolation between audio and control circuits
• Printed circuit board mounts with microphonic isolation

Control and connectivity

• NARCOM-5 remote control included
• 3.5 mm remote connector on rear panel
• Updatable via mini-B USB port
• Front panel controls: volume and selectors
• Alps Blue Velvet volume control

Power supply and consumption

• Off mode: less than 0.3 W
• Deep sleep standby mode: 14 W
• Normal use: 140 W
• Mains power supply: 115 / 230 V, 50 / 60 Hz

Dimensions and weight

• Width: 43.2 cm
• Depth: 30.1 cm
• Height: 7 cm
• Weight: 8.5 kg